19992491 has 2 divisors, whose sum is σ = 19992492. Its totient is φ = 19992490.

The previous prime is 19992457. The next prime is 19992517. The reversal of 19992491 is 19429991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19992491 - 2¹⁰ = 19991467 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19992431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9996245 + 9996246.

It is an arithmetic number, because the mean of its divisors is an integer number (9996246).

Almost surely, 2^19992491 is an apocalyptic number.

19992491 is a deficient number, since it is larger than the sum of its proper divisors (1).

19992491 is an equidigital number, since it uses as much as digits as its factorization.

19992491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 44.

The square root of 19992491 is about 4471.2963444621. The cubic root of 19992491 is about 271.4077864707.

Subtracting from 19992491 its reverse (19429991), we obtain a square (562500 = 750²).

The spelling of 19992491 in words is "nineteen million, nine hundred ninety-two thousand, four hundred ninety-one".